added ColorImageWriter
made ColorImageWriter more error robust
bugfix: ImageReader and ImageCrop create images that own their data, now
changed target type to OBJECT
removed obsolete destructor in MserParametersCollector
bugfix: made Image own its data

This was a problem if the creator of an image was destructed and a
reference to the image was still around. This can happen if a
pipeline::Value<Image> got sneakily casted into boost::shared_ptr<Image>
-- the pipeline gets destructed, the image is alive.
Merge remote-tracking branch 'funkey/master' into catmaid

Conflicts:
	CMakeLists.txt
	Image.h
	io/ImageReader.cpp
	io/ImageReader.h
added initial value to constructor of Image
adjusted ImageStackHdf5Reader for new Image
Merge remote-tracking branch 'funkey/master' into catmaid
adjusted ImageHttpReader and ImageCrop for new Image